Western babies often are missing a key gut microbe common elsewhere

Some animals have little or no bacterial populations in their gut

Gut microbiomes are essential to human health, but many animals have a much smaller, transient, or even nonexistent microbiome. The discoveries have advanced our understanding of the evolution of the human microbiome.

What happens when the gut microbiome is out of whack?

An imbalance in gut microbiome flora can lead to a condition known as dysbiosis. This condition is typically characterized by a drop in microbiota diversity and an increase in harmful unicellular and acellular organisms, such as viruses, that can negatively impact the host's immune system and overall health. Genetics, infections, dietary choices, antibiotics, food additives, artificial sweeteners, and other lifestyle and environmental factors can cause dysbiosis.

Improved 19th-century sanitation meant kids encountered polio later, with worse results

Almost all children likely used to contract poliovirus, but scientists suggest that when infants encountered it very early in life—due to poorer conditions and hygiene—they still had some maternal protection from pregnancy or through breastmilk, so the symptoms were more flu-like.

Probiotics, which are living bacteria and yeasts, are not recommended for most patients

The American Gastroenterological Association in 2020 concluded that although almost 4 million American adults have taken some form of probiotics, health claims about them are not backed in strong evidence. They only recommend their use for a few specific situations: to prevent Clostridioides difficile infection in people taking antibiotics that kill gut bacteria, to prevent necrotizing enterocolitis in preterm infants, and for the management of a complication of inflammatory bowel disease called pouchitis.

Modern conveniences may be contributing to allergy increases

A combination of genetics and how the environment changes our genes are likely contributing to the rise in allergies. But daily conveniences, such as dishwashers and packaged baby food, also change the level of bacterial exposures in early life, with potential implications for allergy development, experts from Mount Sinai Health System state in this video discussion.

Most of the world’s population has difficulty processing lactose—but that’s not an allergy

Lactose intolerance is a digestive condition that occurs when the small intestine has difficulty breaking down lactose, a sugar found in products like milk or cheese, leading to symptoms such as diarrhea or bloating. Almost 70% of the world’s population may have lactose processing issues, particularly in Asia and Africa. This is different from a condition called cow's milk protein allergy—an immune system disorder that can cause hives and anaphylaxis.

Newborns have a strong sense of smell

Babies are drawn to their mother's smell—and the particular odor of their mother's breast milk—within days, even as their vision remains blurry for months after birth. In the womb, the olfactory center also forms in the early stages of development.

Research suggests the cleanliness of the ISS may make astronauts unhealthy

The International Space Station's sterile conditions deprive astronauts of the opportunity to strengthen their immune systems through microbial exposure. To address this problem, future missions may use probiotic-based cleaners and foster diverse microbes in space habitats.

Bidets have been considered taboo throughout US history

While bidets are a typical household essential in Europe, Asia, and South America, they remain uncommon in the US. Associations with infertility, the aristocracy, and brothels helped fuel their unpopularity in the states.

South Asia and sub-Saharan Africa are most at risk from falling pollinator numbers

Researchers at the Harvard T.H. Chan School of Public Health found that declines in pollinator populations would lead to higher rates of nutritional deficiencies, particularly in developing nations. Nations with large populations, such as China and India, would also be significantly impacted.

How a worm helped give the southern US its reputation

"The germ of laziness" that blanketed the southern US for centuries with unshakable fatigue, brain fog, and distended bellies paired with emaciated frames was actually a worm. This parasitic worm lives in the gut, where it can stay up to five years, laying up to 10,000 eggs daily. Hundreds of millions of people worldwide continue to suffer from hookworm infections, often obtained by walking barefoot across infected soil.

Research on bacterial cultures used in yogurt production led to CRISPR's discovery

Scientists learned it was a microbial immune system that could be repurposed to protect dairy cultures from viruses. Today, nearly all yogurt is made with CRISPRized bacteria, as are genetically modified crops like herbicide-resistant corn, wheat, and soy.

Vitamin B1 is linked to gut motility—helping fight constipation—in 2026 research

A study published in early 2026 found a link between vitamin B1 and the successful movement of food through your GI tract, known as gut motility. The work incorporated genetic and survey data about poop frequency to identify genes associated with gut motility and then separately linked poop frequency data with how much vitamin B1 people ingested, theorizing that the vitamin supports the production of acetylcholine, a neurotransmitter that stimulates GI system contractions.

Europeans' arrival to America brought disease to Indigenous populations

Indigenous people lived in the Americas for centuries before the arrival of the first Europeans in the 15th century. Their arrival was disastrous for Native tribes; in addition to being enslaved and losing their land, they had no natural immunity to the diseases brought by colonists. Eventually, up to 95% of the Native American population was killed by illnesses including typhus, chickenpox, and cholera, an event now known as the Great Dying.

Unconditional birthright citizenship is rare outside the Americas

Around 30 countries, mostly in the Americas, grant automatic citizenship by birthplace. Elsewhere—especially in Europe, Asia, and Africa—citizenship typically follows jus sanguinis, based on parental descent rather than location of birth.

Corynebacterium species are particularly responsible for our funky smell

Myriad bacteria contribute to our body odor, but research suggests that Corynebacterium species are strongly associated with the bad smells emanating from adults. Staphylococcus and Cutibacterium genera may also play leading roles.

Learn how your earwax may be determined by genetics—and geography

Researchers have discovered that wet and dry earwax are associated with specific gene variations. Wet earwax is particularly associated with warmer areas of Europe, Asia, and the Americas, suggesting that dry earwax may have been evolutionarily advantageous in cooler climates.

The most critical superbug strains (as of 2024)

The World Health Organization updated its list of the highest priority pathogens known to have developed antimicrobial resistance. Topping the 2024 update is Acinetobacter baumannii, carbapenem-resistant ("CRAB"), which has a mortality rate close to 50% and has evolved defenses against last-line medications. Download the full report here.

Why is there a Vitamin K but no Vitamin F?

The first vitamin was identified in 1913 by an American scientist performing rat studies while investigating dairy cattle nutritional needs. Elmer Vernon McCollum called this first vitamin, found in butter and egg yolk, "fat-soluble factor A." This...

Specific imperfections are needed to make Swiss cheese

Impurities in the milk are critical for the formation of holes in Emmental. The cleanliness at farms today could potentially eliminate the iconic characteristic, though cheesemakers are finding a solution to preserve the holes that help define the cheese.

Inflammaging appears to differ across global populations

Chronic, low-grade inflammation linked to aging is a byproduct of our industrialized lifestyles, according to recent research. The work compared two industrialized populations with two Indigenous, non-industrialized populations in Bolivia and Malaysia, and found that inflammation levels in the Indigenous groups—unlike the industrialized ones—did not seem to differ by age.

Using artificial wombs to improve preterm infant health outcomes

Researchers at a hospital in the US have successfully used artificial wombs to care for preterm lambs and are now looking at the possibility of human trials. This nine-minute video includes interviews with the researchers and explains the reasoning...

In the US, 3.6 million babies were born in 2023

That year, about 40% of the babies were born to unmarried parents, and about 32% of the births were born via cesarean. On average, mothers were 27.5 years old when they had their first child.

Most Westerners don't need more protein, despite the protein boom

You can find the macronutrient in snack bars and pretzels, shakes, and more, even though most normal diets in the West are already protein-heavy with meat and milk. A mix of increased exercise culture and influencer sway has led to a market hungry for it.

Wild chimpanzees have been spotted with leprosy lesions

In research published in 2021, scientists reported discovering cases of leprosy in wild chimpanzees from Guinea-Bissau and the Ivory Coast—marking the first time the disease has been found in any nonhuman species in Africa. They confirmed that leprosy was the cause of the deformities by testing the animals' poop for the presence of the disease-causing bacteria.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

The American cockroach is actually from Africa, an apparent hitchhiker aboard ships carrying enslaved people, with evidence suggesting the bug may have arrived in the New World as early as the 1600s.

In recent years a child anxiety expert has created and tested a novel phobia and anxiety treatment approach for children, focused on changing how parents respond to the fears.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Ebola species have historically been named after where they were discovered, stigmatizing residents who live there, including Bundibugyo, in Uganda.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

About 2,000 US babies are born annually without some portion of their limbs, potentially leading to a lifetime of pricey prosthetics.

An investigation suggests a Scottish island became awash in forever chemicals via seafoam and seaspray—raising questions about what that means for the safety of other coastal areas.

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.

For centuries, it was common to sleep in two shifts: a few hours at the beginning of the night, and a longer period beginning around midnight

Most of the observable universe's volume consists of voids and supervoids—enormous regions of space with little to no galaxies, stars, or light.

Telehealth demand for GLP-1s for weight loss is booming as consumers seek easier access.

Coral reefs get their colors from zooxanthellae—microorganisms that line corals' digestive tracts and provide them with sugars in exchange for a home within this protective tissue.

See how Budweiser's famous Clydesdales spend their days at Warm Springs Ranch, where roughly 70 to 80 of the beer brand's giant horses can be found at any given time.

Up to a million Girl Scouts sell about 200 million cookie boxes every spring, generating $800 million, largely because refusing a child is frowned upon

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

Poison ivy is in the same family as mangoes, cashews, and pistachios—and they all produce oily urushiol in their raw, unprocessed state—but they are typically prepared in ways to avoid causing human discomfort.

One of the most famous portraits ever taken is 'Afghan Girl' (1984) by Steve McCurry, yet the subject Sharbat Gula went much of her life without being identified or benefitting from the image's success.

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

In 2026, Finland was named the world's happiest country for the ninth consecutive year based on its wealth, social safety network, and high life expectancy, among other factors.

The Brothers Grimm were lawyers before they were storytellers, but became interested in fairy tales as they began investigating how rules and customs had been passed down through cultures.

Many legends about George Washington, including his supposed wooden teeth and the story of cutting down the cherry tree, lack evidence.

NBA superstar Victor Wembanyama spent the 2025 summer training with monks in central China to enhance his body and mind.

The Beatles' US label rejected the band's first two singles, 'Please Please Me' and 'From Me to You,' with one executive calling the band 'dead in the water.'